Pulmonary function studies in bird breeder's lung.

Pulmonary function studies were performed at the time of diagnosis in 10 patients, aged between 11 and 51 years, with bird breeder's lung due to exposure of between 9 months and 42 years. The studies were repeated after a varying interval in nine of these patients, following removal from exposure. In initial tests, diffusing capacity was impaired in eight patients and the arterial oxygen tension at rest was below 80 mm. Hg in seven. Five patients had a low vital capacity and three showed evidence of airway obstruction. One patient continued to breed pigeons, against medical advice, and his pulmonary function, repeated after nine months, showed further deterioration. The others with abnormal pulmonary function showed significant improvement on repeat studies. Pulmonary function studies appear to be helpful in the diagnosis, irrespective of radiographic changes, and in the follow-up of patients.